I have one source of power (1 hot wire) for 2 loads (living room lights and breakfast nook lights)

I am replacing the dimmers with Insteon dimmers. The previous switches didn't use the neutrals, but the Insteon switch requires the neutral. The neutrals are in the gang box, but I don't understand what neutrals do or how they connect to the schematic. Can someone help me understand?

Also, when I connect the neutrals the breakfast nook lights stay on regardless of switch position, but the living room lights work perfectly. If I don't connect the neutrals then neither of the lights work. What is happening and why? Can I fix this?


  • Can you include a photo that shows the device boxes and wiring? Or describe how many wires there are, what color they are, what cables they come from, and where they were attached to the previous switches?
    – Tester101
    Commented Jan 16, 2015 at 16:57

2 Answers 2


Without knowing exactly what you've got going on, it's impossible to say for sure what you have to do. It's totally possible that there are no "neutrals" in the box at all, depending on when the house was wired (and by whom).

Here's what the schematic should look like...

Schematic with "neutrals" connected

Basically, any wire that comes "after" a load, and creates a low resistance path back to the "source" is a "neutral". Which means you can further label the diagram as such...

Schematic with all "neutrals" labeled.

The dimmer requires a "neutral", because it itself is a load. So it requires a low resistance path back to the "source" as well.

A wire coated in white insulation, does not make a wire a "neutral".


So figured out the error was not with my understanding of the wires (although i was lacking some knowledge)... The actual problem was a defective dimmer. I tried a different one, and it worked instantly.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.